Target Oriented Approach Can Boost Solar Heating in Food Processing

The Indo-German cooperation project “Solar Payback” for accelerating Solar Heat for Industrial Process (SHIP) has identified food processing as one of the potential industrial sectors as per the study undertaken by Solar Thermal Federation of India (STFI). Figure1 below lists the potential industrial sectors that should adopt Solar Heat for Industrial Process (SHIP) in their various production processes.

Ministry of New and Renewable Energy (MNRE), government of India has been at the forefront promoting Solar Heat for Industrial Process (SHIP) since 2010 and over 30,000 m2 area of SHIP systems have been commissioned in India through fiscal measures from multilateral agencies. India presently is the fourth best global market.

Food processing and its segments

India is the world’s second largest producer of food products second only to China. The food processing industry is one of the largest industries in India and ranks fifth in terms of production, consumption and exports. The Indian food processing market is worth INR 25,000 billion and is likely to achieve INR 50,000 billion by 2024, exhibiting a CAGR of 12.4% during 2019-2024. It constitutes 14 per cent to India’s GDP through manufacturing.

The Solar Payback study reveals food industry and beverages sector has a large heat demand in the temperature range up to 150°C. Common processes are pasteurization of liquid food at 65° to 100°C, cooking at 100°C in meat processing, blanching of vegetables or meat at 65° to 95°C, drying and evaporation at 40° to 130°C in fruit and vegetable processing or cleaning of products and production facilities at 60° to 90°C. Figure 3 below gives the source-wise distribution of energy consumption.

There are over 40,000 food processing industries in India; consisting of, both, small and large entities. Every 1 million m2 of concentrated solar thermal systems under continuous operation basis can result in annual diesel savings of 7 million litres and abate worth 20,000 tons of CO2 annually. The time is ripe to set aggressive target for achieving sustainable heating across all food processing industries. The country has sufficient expertise to design and develop technologies which can result in employment opportunities, as well. However, there is a lack of awareness amongst food processing industries in the country and multiple capacity building workshops can give stimulus to SHIP systems.

Case Study of Agricultural produce drying in Ladakh region

Ladakh region (Leh and Kargil) the northernmost tip of Himalayan India is among the areas that receive the country’s highest solar radiation. On an average, the region has direct normal irradiance (DNI) of average up to 6.5 kWh/m2/for about 150 days in a year. Night temperatures during summer almost plunge to sub-zero. This region produces one of the world’s best varieties of apricot with average production of 8,000 tons annually. Cultivation is only possible during summer and there is a short window of time to pluck, process and transport the fruits. According to most farmers, not being able to pluck or sell their produce within a 2-month period causes losses of more than 50% of the fruit produce. Open drying causes further losses from weather and insects. Quality processes for plucking, fetching and controlled drying can go a long way in preventing losses. Under the Prime Minister’s Reconstruction Plan, the Ministry of Food Processing Industries (MOFPI) explored the possibility of use of solar energy for accelerated drying with qualitative produce that would also make commercial sense. It entrusted the task to National Institute of Solar Energy (NISE) to develop a prototype solar thermal air dryer, which came up with a vacuum tube collector drying system.

The solar collector is a 5.2 m2 aperture area vacuum tube collector. It is joined with a 1m3 drying chamber that can hold 100 kilograms of raw apricots. Phase change material form of storage is used to ensure round the clock drying during dark hours. The solar drying units can be easily modified during installation to provide room heating in the winter thus saving on purchase of firewood. Each unit costs about INR 250,000 and the payback period is three years.

Presently 600 drying units are already commissioned and by the end of year additional 400 units are expected to be operational. They will, combined, save up to 600,000 kilograms of fuelwood and abating 1,000 tons of CO2 annually.

- Jaideep N. Malaviya Project Head Solar Payback, India